The safe and efficient storage of large volumes of liquids and gases has often proven problematic, particularly for liquids and gases that can present a danger to the public or the environment due to flammability, toxicity, or the like. Safe, large volume storage that is also easily and economically accessible is even more problematic. Adding to these problems, the need for such storage is expected to increase with increasing population concentrations. For instance, when considering fossil fuels, many major markets are expected to experience shortfalls in material deliverability in the future due to increases in material demand and insufficient storage capacity, in particular during times of peak demand for fuels, e.g., summer heat waves or cold winters.
Existing large volume liquid and gas storage technologies include both above and below-ground storage. Underground storage includes, for instance, converted oil and gas fields, aquifers, and abandoned mines. Formation of subterranean caverns within existing salt formations has also been utilized to develop large volume underground storage.
Current storage schemes present both economic and safety considerations. For example, the construction of a large number of above ground fuel storage vessels introduces considerable risk in the modern era of terrorism. In addition, and when considering natural gas storage in particular, one storage scheme includes an expensive liquefication process followed by storage in insulated tanks that are expensive to construct and maintain. Moreover, it can be problematic to find locations near major markets where communities will allow the construction and maintenance of large above-ground storage facilities due to safety and aesthetic concerns.
Current underground storage technologies present difficulties as well. For example, the conversion of gas fields, oil fields and aquifers to underground storage facilities as well as the formation of salt caverns all suffer from the fact that suitable locations are often not near existing transportation facilities or market centers. Additionally, converted pre-existing facilities may not be suitable for storing certain materials because of the many containment issues associated with the high permeability of the existing formations. Manufactured salt caverns, while allowing higher deliverability rates as well as having improved impermeability over other types of underground storage, have experienced problems due to the tendency of the salt to flow under high temperature and/or pressure conditions, which can lead to cavern closure in certain situations.
What is needed in the art is technology that can provide underground locations suitable for many desirable uses, and particularly for storage of large volumes of liquid and/or gas. Moreover, what is needed in the art are methods for storing large quantities of fluids in locations not previously considered suitable for underground storage.